A fermentation production process and a chemical conversion process of an organic compound using a saccharide as a raw material have widely been utilized, and a product obtained by the above-mentioned respective processes has been utilized as a raw material for various industries.
At present, as a saccharide to be used as a raw material for these fermentation production processes and chemical conversion processes, those derived from edible raw materials such as saccharide cane, starch, saccharide beets, corn, potato, cassava, saccharide maple, etc., have been mentioned.
However, when these saccharides derived from the edible raw materials are used as a raw material of the above-mentioned processes, there are concerns that price rise of edible raw materials due to expecting population growth in the world and short supply of edible raw materials due to bad weather or climate change. In addition, at the time of food shortages, there is also concern about criticism such as ethical for utilizing edible raw materials for industrial raw materials to compete with an edible use. Thus, it is the problem in the future to construct a process for efficiently producing a liquid (saccharide solution) containing a saccharide inedible raw materials from a saccharide with lower purity containing impurities, or a process which can efficiently convert the obtained saccharide solution to an industrial raw material as a fermentation production raw material or a chemical conversion raw material.
As a method for obtaining a saccharide solution from inedible raw materials, there are mentioned a method in which cellulose or hemicellulose in inedible raw materials is hydrolyzed by using conc. sulfuric acid to a monosaccharide such as a hexose represented by glucose, or a pentose represented by xylose (Patent Document 1), a method in which after subjecting to a pre-treatment to improve reactivity of inedible raw materials, hydrolysis is carried out by an enzymatic reaction (Patent Document 2), or a hydrolysis method by using subcritical or supercritical water, etc.
However, when these methods are employed, cellulose or hemicellulose in inedible raw materials is hydrolyzed to obtain a saccharide such as glucose and xylose, as well as a decomposition reaction of these saccharides also proceeds. By the decomposition reaction of the saccharide, a carbonyl compound is produced as a byproduct, and specifically, for example, an aldehyde such as furfural, hydroxymethylfurfural, glycolaldehyde, formic acid, etc., or a ketone such as dihydroxyacetone or benzoquinone, etc., are formed.
Among these, as a method for removing and converting furfural, etc., it has been known a removing method using wood-based carbide or an activated charcoal (Patent Document 3, Non-Patent Document 1), a removing method using a synthetic resin (Patent Document 4), and an a reducing agent an aldehyde-conversion method (Non-Patent Document 2), etc.